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460
Aristotle and Democritus
Democritus and Aristotle were both Greek Philosophers between 460-322 B.C. Democritus was the first to indicate the existence of an ultimate particle and referred to them as atoms. Aristotle believed that no matter how many times you cut a type of matter in half, you would always have a smaller piece of that matter.This is known as the Atomic Theory.
abyss.uoregon.edu -
Antoine Lavoiser
Antoine Lavoiser was a French chemist born in Paris, France in 1743. Lavoiser stated that mass is neither created nor destroyed in any ordinary chemicalreaction. He believed that the mass of a substance produced by a chemical reaction is always equal to the mass of the reacting substance and referred to this as the Law of Conventional mass.
-nature.commi.mun.ca -
Joseph Proust
Joseph Proust was a French chemist and teacher born in 1754. While performind an experiment, Joseph Proust discovered that a chemical compound always contains exactly the same proportion of elements by mass, this became known as the Law of Definite Proportions otherwise known as Proust's Law. Proust's other discoveries included creating elements from water, which is considered to be his biggest discovery
-princeton.edu -
John Dalton's Spherical Model
John Dalton was an English chemist, meteorologist and physicist born in 1766. Dalton's model demonstrated that atoms were small, unbreakable particles. He stated that each had a certain mass, size, and chemical behavior that determined by what kind of element they were. -
Thomson-Cathode Ray Tube Experiment
J.J Thomson suggested that atoms have different parts . When Thomson performed the Cathode Ray Tube experiment, he took a pair of metal cylinders with a slit in them, connected them to an electrometer, and bent the ray with a magnet. He then seperated the charge from the rays. When the ray entered the slit there was a negative charge. Thomson believed that atoms were divisible and that the negative charges were the building blocks.
-aip.orgchemheritage.org -
Thomson-Electron
The electron was first theorized by Rihcard Laming between 1838 to 1851 and G. Johnstoney in 1874. The actual discovery was made by Thomson in 1897 in which he stated that the electron is a subatomic particle with a negative electric charge (e-) electrons are the smallest and most numerous of the subatomic particles. Thomson was a British physicist born in 1856 who attended Owens College at the young age of 14. Thomson is known mostly for his Plum Pudding Model and his numerous discoveries. -
Max Planck
Max Planck was a German theoretical physicist born in 1858. Planck studied at the University of Munich and Berlin. Planck generated the theory that physics based on the principle that matter and energy have the properties of both particles and waves. He also believed that energy can be emitted or absorbed by matter only in small units called quantras. This is now known as the Quantum Theory. -
Thomson's Plum Pudding Model
Thomson's Plum Pudding Model demonstrates electrons being surrounded by positive charges. Thomson states that the protons are the pudding and the electrons are the plums. -
Rutherford's Nuclear model
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Ernest Rutherford-Gold Foil Experiment
Harts Geiger and Earnest Marsden helped Rutherford demonstrate the existance of the atomic nucleus and also disproved the plum pudding model. Rutherford shot a beam of alpha particles at a sheet of gold foil, and several of the particles were bounced back. Rutherford concluded that the reason for this was that there was a nucleus deflecting the particles
-myweb.usf.edu/~mnight/goldfoil.html -
Ernest Rutherford-Nucleus
The nucleus consists of protons and neutrons and is located in the center of the atom and was discovered by Ernest Rutherford -
Neils Bohr
Bohr was born in Copenhagen in 1885 and studied at Copenhagen University in 1911. After being influenced by Planck,Thomson, and Rutherford, Bohr began studying the properties of atoms. Bohr is best known for his atomic model of the model (Bohr model). His model indicated a the atom with a positively charged nucleus and orbiting electrons -
Ernest Rutherford-Proton
William Prout came up with the idea of a subatomic particle with a positive electric charge of 1(p+). The proton later got its name in 1920 from Ernest Rutherford. Rutherford was a chemist and physicist in New Zealand. He attended Canterbury College between 1890 to 1894. He then left New Zealand and workded with J.J Thomson at Cambridge University's Cavendish Laboratory. -
Erwin Schrodinger's Quantum Mechanical Model
Erwin Schrodinger was an Austrian physicist born in1887. The quantum mechanical model is based off of the quantum theory. Schrodinger's model show a representation of the waves believed to make it impossible to know the position and velocity of electrons. -
Werner Heisenburg
Heisenburg was a German theoretical physicist and one of the key creators of quantum mechanics. The uncertainty Principle is the origin of Heisenburgs uncertainty relations principle and uses this formula:
DxDp>h/2(3.14)
The principle states that the momentum and position of a particle cannot be precisely determined at the same time. -
James Chadwick
James Chadwick was an English physicist born in Bollington, United Kingdom in 1891.Chadwick studied at Gonville and Caius College, Cambridge, University of Cambridge, and University of Manchester. Chadwick discovered this subatomic particle and claimed that it had no net electric charge (n0). He called this the nuetron. Nuetrons are so small that it cannot be seen, even with an electon microscope. Chadwick has earned several awards, one of them being a Nobel Peace Price in Physics -
Sources
-Hyperphysics.phy-aste.gsu.edu
-aip.org
-neutrons.ornl.gov
-library.thinkguest.org/27930/uncertainty.htm
aip.org/history/heisenburg/po8.htm
-dwb.unl.edu
